function f = elliptic_ux(x,y)
global alpha theta;
f=0.2e1*(x.^2+y.^2+eps).^(-1+1/ alpha).*(x.*sin(0.2e1*(atan2(y+eps,x+eps)+theta)/alpha)-cos(0.2e1*(atan2(y+eps,x+eps)+theta)/alpha).*y)/alpha;